Cold crystallization and photo-induced thermal behavior of alkyl-derivatized diarylethene molecules

The thermal behavior of alkylated diarylethene molecules (2,3-bis(2,4,5-trimethyl-3-thienyl)-N-alkylmaleimides; DAE-Cn) was investigated. DAE-C1 and DAE-C2 exhibited cold crystallization, which is a heat-storage phenomenon. In addition, DAE-Cn showed photoisomerization; the open-ring isomer O-DAE-Cn was formed by visible light irradiation and transformed to the closed-ring isomer C-DAE-Cn by UV light irradiation. X-ray diffraction and optical microscopy analyses revealed that O-DAE-Cn exhibited cold crystallization and C-DAE-Cn showed poor crystallinity. UV irradiation (365 nm) inhibited cold crystallization, and visible light irradiation (525 nm) triggered cold crystallization, suggesting that heat storage by the cold crystallization of DAE-Cn can be photo-controlled.

Automated summary

The thermal behavior of alkylated diarylethene molecules (DAE-Cn) was investigated. It was found that DAE-C1 and DAE-C2 exhibited cold crystallization and DAE-Cn showed photoisomerization. Visible light irradiation resulted in the formation of the open-ring isomer, while UV light irradiation transformed it into the closed-ring isomer. Cold crystallization could be inhibited by UV irradiation and triggered by visible light, indicating that heat storage could be photo-controlled.